1. Field of the Invention
This invention relates to frozen desserts prepared by using, as an emulsifier, elaidic acid esters of polyhydric alcohols selected from the group consisting of glycerol, propylene glycol, sorbitol and saccharose.
2. Description of the Prior Art
Various frozen desserts such as ice cream, ice cream of low fat content, ice milk, fruit sherbets, frozen custards and mellorine have been prepared by freezing homogenized oil-in-water emulsions each of which contains oil and fat, skim milk, saccharose, flavorings, water and an emulsifier. Monoglycerides of fatty acids have conventionally been used, as emulsifiers, in the preparation of various frozen desserts and have exerted very important effects on the production processes.
When used as emulsifiers, the monoglycerides of fatty acids mainly function to improve foamability, to impart solidity and to improve the shape-retaining property of the frozen dessert. Illustrative monoglycerides of fatty acids conventionally used for these purposes include the monoglyceride of stearic acid, the monoglyceride of oleic acid and mixtures thereof.
The reasons for the fact that the monoglyceride of stearic acid (glyceryl monostearate) and the monoglyceride of oleic acid (glyceryl monooleate) have been generally used for this purpose are that not only are the starting fatty acids for these glycerides available most easily, but also these glycerides have special advantages for such use. In brief, the monoglyceride of stearic acid has a strong emulsifying force and does not deteriorate the flavor and taste, and on the other hand, the monoglyceride of oleic acid can considerably improve the shape-retaining property.
However, these glycerides have serious disadvantages, and thus they cannot be considered as the ultimate or best emulsifiers. Specifically, the monoglyceride of stearic acid has a very poor shape-retaining property, and the monoglyceride of oleic acid causes serious deterioration of the flavor and taste and it has the further disadvantage that it increases greatly the viscosity of the starting mixture for preparing the frozen dessert which is disadvantageous when the starting mixture is aged or digested.
For this reason, stearic monoglyceride and oleic monoglyceride are mixed together for practical use. Even when the mixed composition is used, the deterioration of flavor and taste due to the oleic monoglyceride is not completely obviated. Accordingly, it is desired to decrease the amount of oleic monoglyceride used in the mixture from the standpoint of flavor and taste, but to increase it for improving other desired qualities or properties such as the shape-retaining property. In consideration of the contradictory requirements mentioned above, the practical mixing ratio of oleic monoglyceride to stearic monoglyceride is in the range of 20 to 30 percent, based on the total weight of the mixture of the two monoglycerides.
The amount of the emulsifier in a starting mixture for preparing ice cream in the most generally practiced process for making ice cream is from 0.20 to 0.35% by weight, based on the total weight of the ice cream mix, so that the amount of oleic monoglyceride, based on the weight of the starting ice cream mix, is 0.04 to 0.12% by weight.
Oleic monoglyceride affects seriously the flavor and the taste of the ice cream, even though the used amount thereof is so small.